LR 6.6 (Win x64) performance at 4K is unacceptably slow

I've recently spent £1700 on a state of the art Dell laptop with a 4K screen, i7 CPU, 16GB RAM, SSD and Quadro M1000M GPU, but the poor performance I'm experiencing across the board is so frustrating that I've had to give up on using 4K altogether and drop the screen resolution to 1920x1080 to make LR usable.

I understand that working with 4x the number of pixels will result in a performance hit when in Develop mode, but that doesn't explain why EVERYTHING else about using LR is slow, including simple stuff like switching from Develop to Library taking a second or two (with a stuttered redraw too) and even when I simply select a bunch of images and try to click & drag them into another folder there's a long delay between the click and getting the stack of images icon/pointer to drag around.

It all makes LR incredibly frustrating to use at 4K and makes me wish that I hadn't upgraded and wonder whether LR is a dead end for me as 4K has been around for years now and LR clearly still doesn't support it properly.

I've read other threads about performance tweaks but they've all had no effect apart from rendering previews at 1:1 which I'm now doing (it slows down importing but at least I can walk away from that and reap the benefits later). And I'm not experiencing performance issues in any other apps.

I'll make do for now in HD resolution (which looks rubbish compared to the 4K I was getting used to) but LR7 had better deliver a complete performance overhaul and make smarter use of my laptop's CPU & GPU power in tandem, as it's *long* overdue.

Dear Marcus
Welcome to the 4k slow club.
Have you tried capture one?
Im also waiting for an improvement and wish adobe will change the underlying code as it seems to got to its limits. With all the rendering of 1:1 preview and smart preview and now 4k. I think they need to go back to the drawing board in order to be ahead of the game and not chasing it. When i work on my 10y old 22mp files i get today reasonable performance but not with my todays 80mp files. That's why I am looking to move to capture one.
I hope that lightroom 7.0 next year will bring a new super fast architecture for raw processing utilising what they are already doing in video rendering using the all cpus and gpus 1000% and not a fraction of it.
We all have patients but it is costing us in time alot of time waiting for the software to respond and that is a real pain when your bottle neck is the software and not the operator...